What happens when the lead gameplay designer at Playdead (Limbo) strikes out on his own with a side project? 140 is what takes up Jeppe Carlsen's free time. It's a rhythm-based minimalist platformer that he's developing with Playdead audio programmer Jakob Schmid and graphic artists Niels Fyrst Lausdahl and Andreas Arnild Peitersen.

The game earned its IGF nomination in the audio category, and in this interview, Gamasutra speaks to Carlsen and the team about marrying platforming, audio, and visual art into a cohesive whole.

What is your background in making games?

Jeppe Carlsen: I am currently working at Playdead as lead gameplay designer, and 140 is my spare time pet project. My background is in computer science at university, and after finishing my master's degree I started working as a game programmer. During my work at Playdead, I found that I had a knack for designing simple yet challenging puzzles, which was my main contribution to Limbo.

Jakob, who created music and sound design for 140, works as audio programmer at Playdead. He was hired by Playdead after Limbo.was completed.

Niels and Andreas, who designed the visuals, are graphics and motion designers outside of the games industry.

What development tools are you using?

JC: The game is done in the free version of Unity3D. All audio was produced using Ableton Live.

How did you come up with the concept?

JC: The game concept was developed very iteratively. I started working on a retro platformer framework in my spare time, in which the main character had the ability to throw a ball that would fly in a straight horizontal line and bounce between walls.

When adding different audio samples to the different walls, the bouncing balls resulted in beats created by the environment itself. Switches on the walls controlled different environment elements, and made the whole level "dance" to the music. I was onto something, and even though the game changed to something rather different (and simpler) over the next two years, it was at this point I got obsessed with merging platforming and beats, and 140 is ultimately the result of this obsession.

How long has your team been working on the game?

JC: I have been working on in it my spare time with a steady dedication for longer than two years, completely redesigning the game and its levels a few times in the process. I had no idea I would be working on this for so long. But the way I make games can pretty much be boiled down to: implement a ton of different ideas, delete most of them, repeat until I'm too tired. It is all about getting some kind of consistency to it, where everything feels like it fits together and complements each other.

Jakob is a close friend from university, and I have always admired (read: totally envied) his skills as an electronic musician. I have bounced my ideas off him from the very beginning, and he started contributing a bunch of test loops for me to play around with. Along the way, he became more deeply involved in the process as composer and sound designer. Originally, the music was 120 BPM, but Jakob was keen on changing it to a more energetic 140 BPM, which immediately resulted in all the level design of the game breaking. As it turned out, the new tempo was a great fit, and ultimately provided a title for the game.

Niels and Andreas (graphics) joined the project about a year ago, and we agreed to keep the game completely abstract.

Niels Fyrst Lausdahl: The main idea for the visual look of the game, was to make it as simple as possible to state the importance of the sound. We wanted to make it bold and clear and not go with the typical anthropomorphic game character and a concrete environment.

What was the inspiration for the music and sound design?

Jakob Schmid: One of the primary challenges of 140 was to create elements that simultaneously acted as musical elements and sound effects for game elements, the behavior of which are governed by game logic and level design.

Creating and discovering sounds that could fulfill this dual role was an interesting process. Although the audio was developed using modern tools, it conceptually adheres to certain limitations of Sega Genesis and Commodore Amiga audio hardware, specifically the combination of FM synthesis and samples with a low sample rate. All non-sample-based instruments have been synthesized from scratch using FM synthesis, a rewarding approach, as the exploration of the space of FM sounds constantly provides surprising results.

Have you played any of the other IGF finalists? Any games you've particularly enjoyed?

JC: Only played a few. I am huge fan of Terry Cavanagh and Super Hexagon is up there with the best of his work.

What do you think of the current state of the indie scene?

JC: 2012 has been very shallow in terms of triple-A games, and all my truly memorable gaming experiences have been in the indie space: Spelunky, Dyad, and Fez -- just to name a few, that both Jakob and myself have been obsessing over.

What's your guiding principle for marrying audio and gameplay — i.e. do you work toward a concept such as synaesthesia?

JC: 140 is not a strict rhythm game, in the sense that you don't tap or move directly to the rhythm. The rhythm aspect is more subtle, and something the player has to take in on his own. The game is pretty merciless in terms of timing, and is intentionally very vague in its visual clues, but the audio is always there to guide you. Every single challenge is designed to encourage you to search for audio cues, and synchronize your movement with those cues to succeed.